Threading device for yarn heaters

ABSTRACT

A TWO-SIDED CONTACT HEATER FOR ONE OR MORE THREADLINES IS THREADED UP BY MEANS OF A GUIDE DEVICE TRAVELING ORBITALLY AROUND THE HEATER ON AN ENDLESS CHAIN.

Fell 2, 1971 c. H. J. cocKRoFT THREADING DEVICE FOR YARN HEATERS Filed July 12', 196e INVENTOR 4 SST VZ/ ATTORNEYS United States Patent O 3,559,255 THREADING DEVICE FOR YARN HEATERS Christopher Hugh John Cockroft, Pontypool, England,

assignor to Imperial Chemical Industries Limited, London, England Filed July 12, 1968, Ser. No. 744,464 Claims priority, application Great Britain, July 19, 1967, 33,229/ 67 Int. Cl. D021' 13/00 U.S. Cl. 28-62 3 Claims ABSTRACT OF THE DISCLOSURE A two-sided contact heater for one or more threadlines is threaded up by means of a guide device travelling orbitally around the heater on an endless chain.

The invention concerns improvements in or relating to heaters for travelling yarns.

BACKGROUND TO THE INVENTION Yarn heaters form an important part of apparatus for processing travelling yarns, as, for instance, apparatus for heat-relaxing or twist-setting synthetic lilamentary yarns.

As throughput speeds increase, with improvements in the processing equipment and means for winding up the yarns, so is there a demand for improved heating efliciency, which ultimately, at the rates of travel involved, can only be met by lengthening the heaters themselves.

It is already known to militate against the awkwardness of overlong heaters by providing for at least one reversal of direction of the yarn through the heater, the yarn being led around a pulley at one end of the heater to enable at least two spans of the travelling yarn to be heated therein either by radiation and convection or by contact with two heated plates forming the sides of the heater, which plates may be hinged for ease of threading-up. The said pulley may be movable, for instance on an endless chain mechanism, from the bottom of a vertically mounted heater where the yarn or yarns will be threaded-up, to the top, operative position, with the yarn paths extending up and down the heater.

It has been appreciated by us, however, that there are advantages in having a two-faced contact heater, with a single internal heating element or thermal circulation means therein; but such a heater presents a ditliculty in threading-up, if it is a very long one, as it is not possible to thread up merely by raising a pulley.

The present invention is concerned with the provision of a two-sided contact heater having means for automatically threading-up one or more yarns in contact therewith.

SUMMARY OF THE INVENTION According to the invention, a yarn heater assembly comprises a longitudinally and upwardly extending heating member adapted to be mounted on a frame, the outwardly-facing surfaces of which heating member are adapted for contact by a travelling yarn or yarns, means for supplying heat to said heating member, a grooved pulley mounted at the upper end and on the mid-line of said heating member, an endless chain mounted for orbital rotation around said heating member and pulley in a plane parallel to the length dimension thereof, a cantilever arm mounted perpendicularly on said endless chain for rotation therewith, two horizontally-spaced! hook-shaped thread-guides mounted on said arm for one or more yarns to be threaded-up around said heating member, said hook-shaped thread-guides having their open sides uppermost when said arm is in any position on the upward portion of its travel, and fixed threadguide means at the lower end of said heating member for guiding said yarn or yarns into and out of contact, respectively, with the lower end-portion of said heating member.

Conveniently, said heating member comprises two heated plates mounted back-to-back; and, preferably, the means for supplying heat to the plates is a single electric resistance heater mounted therebetween. Preferably, also, the plates have a slight convexity of surface, equivalent, say, to a radius of curvature of 140 feet for a 6 foot height heater.

Although an endless chain is specified for the means for carrying the threading-up arm in orbital rotation around said heating member, it is to be understood that any endless band may be employed instead, a chain being the most convenient form of this type of transporter.

SPECIFIC EMBODIMENT In one particular use for a yarn heater assembly ac`- cording to the invention, two threadlines are threaded-up in parallel, to run in twin grooves along the outwardlyfacing surfaces of the heating member in opposite directions and around twin grooves in the pulley at the upper end of the heating member. In this use, the threadlines severally are given a false twist in opposite twist directions, which twist is set by heat from the heater assembly.

In this case, the cantilever arm has two pairs of hookshaped thread guides, one pair for each thread-line.

Each pair of such hook-shaped thread-guides co-operates with the fixed thread-guide means to enable bights to be formed in each threadline, which bights are then extended in size by upward movement of the cantilever arm when the endless chain is set in orbital motion.

Whether one or more than one is required to be threaded up around the heater assembly, the operation of the automatic threading-up part of the apparatus is similar, in that the running yarn is laced up around the fixed thread guide means adapted to guide it into contact with the heated plate which is to be contacted in the upward movement of the yarn, thence around an inner one or more hook-shaped thread-guides on the arm then positioned level with the bottom of the heated plates and at the starting point for the upward run of its orbital movement, outwardly therefrom to an outer one or more hookshaped thread-guides thereon, and finally, around pref'- erably another xed thread guide means adapted to guide the yarn out of contact from the heated plate which is to be contacted in the downward movement of the yarn.

After the lacing-up has been accomplished, as by a portable suction gun, a chain drive mechanism, e.g. an electric motor, is started, to rotate the endless chain in orbital movement, and the bight or bights of yarn are slowly drawn out, one side thereof leading across the side of the heater assembly and the other leading parallel to the heated plate which is to be contacted during the upward movement of the yarn or yarns.

Once the cantilever arm has completed its upward movement and then moved around the grooved pulley at the top of the heater assembly, the yarn or yarns drop out of the open, then downwardly-facing, sides of the hook-shaped thread-guides and fall into the appropriate slot or slots of the grooved pulley. Threading-up is thus achieved automatically.

When, for example, two threadlines are being threaded simultaneously, as in the false twist process above referred to, the lateral spacing of two inner hook-shaped threadguides is equal to that of the grooves in the grooved alley and in the heated plates.

By suitable shaping of the hook-shaped thread-guides, to determine the amount of curvature of the hooked ends,

` it is possible and necessary so to differentiate the inner 3 and outer guides as to ensure that the outer guides will not release the yarn until the cantilever arm has passed through the zenith of its critical movement (say, by 60), to be in a position for the yarn to be released by the inner guides.

In practice, this means shaping the inner guides with no inward turn-over of the hooked ends, whilst shaping the outer guides with an amount (for example, 60), of inward turn-over.

Mechanism operates to stop the chain drive, and hence arrest the orbital movement of the cantilever arm, when the latter has arrived near to the bottom of the heater assembly.

In order that two threadlines shall be maintained out of interfering contact with each other during lacing up, and while the automatic threading-up of the heater assembly is taking place, it is necessary to dispose the hookshaped thread-guides and the fixed thread-guide means in appropriate manner.

Thus, the two sets of xed thread-guide means should be spaced heightwise from each other, as well as laterally according to the depth of the heater assembly, with the guiding-on thread-guide means lower than the guiding-off means.

Similarly, the two outer of the hook-shaped guides on the cantilever arm should be spaced heightwise from each other, with the lower one displaced laterally inwardly from the other by a small amount. Also one co-operating pair of inner and outer hook-shaped guides should be spaced depthwise by a small amount from the other such co-operating pair.

In addition, a guide bar may be fitted to and along the lower portion of the side of the heater assembly, with its end curved outwardly to extend perpendicularly therefrom at the height level of just above the upper fixed thread-guide means, in order to keep the thread-lines clear of any insulating cover down the length of the side of the heater, and in order to help maintain the thread-lines separate at the lacing-up position.

Preferably, the grooves in the grooved pulley are initially inwardly sloping, say at 45 ending finally in rectangular troughs.

DRAWING The invention will now be described by reference to the accompanying drawing which is merely illustrative of the invention and in which FIG. 1 is an oblique side elevational view of a yarn heater assembly according to the invention; and

FIG. 2 is a section through A-A of FIG. 1.

In the drawing longitudinally and upwardly extending heating member 1 comprises a two-faced plate (or two plates mounted back-to-back) adapted to be heated by internal electric resistance means (not shown) and presenting two outwardly facing grooved surfaces for a pair of yarns Y1 and Y2 to run in contact with along grooves 3, 5. Guard means 7 is fitted in front of heating member 1.

At the rear of heating member 1 are mounted sprockets 9, 11 around and by which endless chain 13 is adapted to be driven in orbital rotation around heating member 1. Chain guard means 15 is mounted between heating member 1 and said sprockets. A groove pulley 16 is mounted at the upper end of heating member 1.

Cantilever arm 17 is mounted for rotation with said endless chain 13 and is shown in solid lines at the initial lacing-up position at the bottom of the heater assembly and in broken lines at a position immediately after passing through the zenith of the orbital rotation.

Two pairs of horizontally spaced hook-shaped threadguides 19, 19 and 21, 21' are mounted on cantilever arm 17, the outer ones, 19' and 21' being aflxed to cross-piece 23 at the end of the arm. These outer thread-guides 19' and 21 have a small amount of inward turn-over; while the inner thread-guides, 19 and 21, have none.

Guide bar 25 is attached by support 27 to heater guard means 7, and serves to keep the two thread-lines separate at lacing-up and while the cantilever arm is rising to the zenith of its orbital rotation. The guide bar also serves to keep the thread-lines clear of contact with the heater guard means 7 during the threading-up of the assembly.

Fixed thread-guide means 29, 29 for the ingoing yarns and fixed thread-guide means 31, 31 for the outcoming yarns are positioned as shown and are aflixed to the frame of the heater assembly (although not so shown in particular detail).

The apparatus of the invention is particularly suitable for high speed yarn processing, such as false twist crimping in a combined drawing and false twist crimping process, where speeds of 2000 feet/ minute are possible, and hence very long heater contact is desirable. In such a case, a heater height of 6 feet is exemplary of the dimensions to be accommodated; and the automatic threading-up provided by the apparatus obviates the necessity for staging on which an operator can stand to reach the top of the assembly, as well as ensuring that the thread-lines are indeed threaded-up accurately in their appropriate grooves.

It will be understood, of course, that the heater of the invention may be uprightly mounted vertically, or at angles to the vertical in either the place of the depth of the heater (i.e., in the plane of the back-to-back mounting of the heated plates) or in the plane at right angles thereto.

Thermostatic control of the heating element or elements will also usually be provided, so as to maintain constant the temperature of the heated plates or any portion thereof according to any desired temperature gradient.

I claim:

1. In a yarn heater assembly consisting of a longitudinally and upwardly extending heating member the outwardly facing surfaces of which are adapted for contact by at least one travelling yarn, and a grooved pulley mounted at the upper end and on the mid-line of said heating member, the improvement comprising an endless chain mounted for orbital rotation around said heating member and pulley in a plane parallel to the length dimension thereof, means for rotating said chain, a cantilever arm mounted perpendicularly on said endless chain for rotation therewith, two inner and outer horizontally spaced hook-shaped thread-guides mounted on said arm for each yarn to be threaded-up around said heating member, said hook-shaped thread-guides having their open sides uppermost when said arm is in any position on the upward portion of its travel, and fixed thread-guide means located at the lower end of said heating member for guiding said yarn into and out of contact, respectively, with the lower end-portion of said heating member.

2. A yarn heater assembly according to claim 1 in which the outer one of the horizontally spaced hookshaped thread-guides has an amount of inward tum-over of the hooked end, and the inner one has no inward turnover of the hooked end.

3. A yarn heater assembly according to claim 1 in which a guide bar is fitted at the lower end-portion of said heating member to keep the yarn clear of said heating member during threading-up.

References Cited UNITED STATES PATENTS 2,794,542 6/ 1957 Vandenburgh et al. 28-62(UX) 3,094,761 6/ 1963 Dudzik 28-62 3,166,822 1/1965 Starkie 28-62(X) 3,321,904 5/1967 Horvath et al. 28-62(X) 3,443,371 5/1969 Ward 28-62(X) 3,448,572 6/1969 Meronen 28-62(X) ROBERT R. MACKEY, Primary Examiner U.S. Cl. X.R. 57-34 

